This invention relates generally to a method and apparatus for use with an electronic implantable medical device for protecting the device from physical and/or electrostatic discharge damage prior to medically implanting the device in a patient""s body. Moreover, preferred embodiments of the invention afford the ability to functionally test the device without removing it from its shipping container prior to implantation.
Many types of electronic medical devices are known which are intended for implantation in a patients body. Although these devices vary widely in design, they typically include a housing containing electronic circuitry connected to two or more electrodes which extend exteriorly from the housing (or one or more electrode when the housing is the other electrode). The circuitry can, for example, include a functional circuit (e.g., a pulse generator), a power supply circuit (e.g., rechargeable battery), and a transceiver for wirelessly communicating with an external controller. Implantable medical devices of this sort are useful in a variety of applications for stimulating muscle or nerve tissue and/or monitoring body parameters.
To minimize device failure and maximize device reliability, it is important that an electronic medical device be properly handled along the entire chain from manufacturing, through shipping and storage, and on to the medical procedure for implanting the device in a patient""s body. For example, improper handling can subject the device to physical damage and/or component damage due to electrostatic discharge (ESD).
The present invention is directed to a method and apparatus for protecting an electronic implantable medical device prior to it being implanted in a patient""s body. More particularly, a method and apparatus in accordance with the invention affords protection to the medical device from just after manufacture to just prior to implantation. Protection is afforded against electronic component damage due to electrostatic discharge and/or physical damage due to improper handling.
Embodiments of the invention are particularly valuable when used with small fragile medical devices which often comprise an electronic circuit housing having a diameter of less than 6 mm and an axial length of less than 60 mm. The housing typically contains electronic circuitry which is electrically connected to first and second electrodes which extend exteriorly from the housing.
A preferred apparatus in accordance with the invention is comprised of a circuit board having first and second spring clips mounted on the board.
The spring clips are configured to receive and releasably grasp the electrodes of a medical device housing to support the housing just above the surface of the circuit board. First and second conductive paths are formed on the circuit board extending between the first and second clips for shunting electrostatic discharge currents to prevent such currents from passing through the device electronic circuitry. Preferably, the respective shunt paths include oppositely oriented diodes, preferably comprising diodes which emit light (i.e., LEDs) when current passes therethrough.
In accordance with the invention, a medical device is preferably mounted in the protective apparatus as a late step in the device manufacturing process. The protection apparatus/device combination is then placed into a shipping container. The combination remains engaged until the device is ready for medical implantation in a patient""s body. The shipping container preferably includes a transparent window through which the light emitting diodes are visible.
In a preferred method in accordance with the invention, the medical device is sterilized, e.g., using steam or ethylene oxide (ETO), after being placed in the shipping container.
A significant feature of the invention allows the medical device to be functionally tested while in the shipping container. More particularly, exemplary medical devices include (1) transceivers which permit wireless communication of commands and data between an external controller and the device electronic circuitry and (2) battery charging circuits which extract energy from an external power source, e.g., via an alternating magnetic field, for charging a device battery. In accordance with the invention, a medical device can be functionally tested while still in the shipping container by transmitting a command or activation signal to the device. If the device is functioning properly, it will respond in a particular manner, as by outputting a sequence of pulses whose characteristics (e.g., frequency, pulse width, etc.) indicate proper operability. This output pulse sequence drives the protection apparatus LEDs which can be monitored to detect whether the device is operating within specifications. Additionally, the device battery can be charged while still in the shipping container by an external power source.